Automatic data capture has been a continuing concern of advanced thinkers in the field of drafting and design automation since the start of computer aided design (CAD). Although CAD systems have been in use for over ten years, there are still mountains of manually prepared drawings in the world today. In fact, recent studies show that there are over 2 billion active drawings in the United States alone. Most companies file thousands of drawings in their vaults, with approximately 20 percent active each year. It is estimated that 10 percent of the drafting effort in the United States is expended merely in drawing maintenance. During use, they become dirty, smudged or torn and must be refurbished regularly. One long standing problem has been how to get these drawings into a CAD system for automatic data updating and to avoid degradation of the file material. Automatic data capture systems have recently been developed for solving such problem.
Installing a CAD system is a major decision that involves not only cost factors, but the problem of how to manage the capture of data from older drawings and new ones that continue to be prepared. One problem inherent in the use of data capture systems is that of handling the documents. More particularly, in many systems, the document is inserted into a receiving area of the machine until its edge abuts with an upper and a lower drive roller and pressure roller which are intimately in contact with each other for receiving the edge of the document along the contact edge of the rollers and driving the document therebetween in a forward direction. One problem associated with this type of document feed into abutting rollers, which are idling and waiting for the document to be inserted, is the hazard of damaging the document edges as they are pulled by the rollers. Some document handling systems provide document guides to assist the operator in feeding the document to the rollers in an aligned manner to thereby present the entire document edge rather than a corner of the document to the rollers. However, the human factor requiring the operator to exactly align the document is one factor in the damage caused to the document. Other human factors contributing to document damage occur when the operator may push the document against the drive rollers and, also, the reflex action which may occasionally occur when the rollers initially pull the document away from the operator whereby the operator responds instinctively by pulling the document back.
Various types of document handling and document conveying systems are known wherein the document is inserted between a drive roller and a pressure roller. For example, in Von Namen U.S. Pat. No. 3,761,075 , the pressure roller is moved away from the drive roller and a document stop mechanism operates to insert a document stop element in the path of the document for the purpose of aligning the leading edge of the document. A secondary document conveying mechanism is required to clamp and control the document in its alignment position until the primary document control means engages the document between the pressure roller and the drive roller for controlling movement of the document. This additional document control and alignment means over and above the simple drive mechanism for the document, with consequential higher manufacturing costs and possible additional maintenance problems. Another type of document handling system is the moving belt type disclosed in Rothbart et al U.S. Pat. No. 4,424,535 wherein a high speed document manipulator includes a moving belt arrangement for reversibly translating a document and for turning the document over so as to be able to read both sides of the document. This type of document handling system requires a large belt and table working area as well as a vacuum system for flipping the document.
Therefore, it is an object of the present invention to provide a document handling system of the drive roller and pressure roller type wherein the document is initially received and moved in a simple manner and without complex and bulky apparatus while at the same time protecting the document from tearing and other damage at the document edges. It is another object to provide a document handling system incorporating the drive roller and pressure roller which avoids the damage to the document often caused by operator errors. It is another object to provide a technique for handling documents in an automatic data capture system having a video digitizer. It is a further object to provide for document handling prior to normal scanning in an automatic video digitizer system.